How to install a compressor in a freezer

Updated April 17, 2017

The compressor in a freezer can become defective with use. The compressor windings may burn out or the valves can leak rendering the compressor inoperative. With careful observation you can become an expert in the installation of a freezer compressor. Whether you have an upright freezer or a chest type freezer, the procedure is the same.

Remove the refrigerant from the freezer unit. Connect the gauges to the freezer and the recovery machine using the piercing valve.

Unplug the freezer and plug in the recovery unit. Turn on the recovery machine and allow it to run until the compound gauge reads "0" psig.

Close the gauge valves and close the refrigerant tank valve. Remove the gauge hose and piercing valve from the compressor tube.

Light the acetylene torch and unsolder the two lines attached to the compressor. Use the locking pliers to pull each line from its soldered joint while heating it with the acetylene torch.

Secure mounting bolts and tighten securely. Insert the suction and discharge lines into the fittings on the compressor. Put some flux on the joints and solder the joints using the propane torch and silver solder. Attach the piercing valve to the third tube protruding from the compressor. Solder the end shut.

Use the adjustable wrench to remove the four mounting bolts that hold the compressor in place. Hold the compressor firmly and lift it off its base. The new compressor should be an exact replacement and should fit on the same mounts. Prepare the new compressor by removing all rubber seals from protruding pipes. Attach rubber mounts to the four mounting points.

Replace the dryer whenever the system is opened to the atmosphere. The dryer is located at the outlet of the condenser. It is a small cylindrical unit. Unsolder it with the acetylene torch and solder the new dryer to the condenser and the capillary line.

Attach the manifold gauge. Attach the vacuum pump in place of the recovery machine. Open the blue handle on the manifold gauge and start the vacuum pump. Allow the vacuum pump to run for 20 minutes to an hour. You should have a good vacuum at least 29 inches Hg vacuum. Close gauge and stop vacuum pump. The unit should hold the vacuum. This indicates that there are no leaks.

Pinch the process tube in front of the piercing valve with the pinching tool. Remove piercing valve and solder hole shut.

Attach a refrigerant drum with clean fresh refrigerant, in place of the vacuum pump. Purge air from the lines and break the vacuum. Start the compressor. Continue charging using the frost line method. That is visually inspecting the evaporator. When it is fully frosted it is fully charged. Close the gauge. Close the refrigerant drum.


Glossary Pinch off tool---used to close process tube Process tube -- used to charge unit through Adjustable wrench -- used to tighten bolts Acetylene -- a fuel gas Flux -- a paste used to prevent tubing from oxidising during soldering Solder -- a low temp melting alloy Evaporator -- the part of the freezer that gets cold Condenser -- gives up heat

Things You'll Need

  • Acetylene torch
  • Flux
  • Silver solder
  • Flint lighter
  • Piercing valve
  • Locking pliers
  • Adjustable wrench
  • Vacuum pump
  • Manifold gauges
  • Flashlight
  • Recovery machine
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About the Author

Martha Richardson began her journalism career as a newspaper reporter in 1992. She has written articles for the Printmaking Council of New Jersey and featured community organizations on "Access New Jersey." Richardson has a Bachelor of Arts in journalism. She graduated from Rutgers University in 1994.